POS0733 REPEATING TEMPORAL AND AXILLARY ARTERY ULTRASOUND SCANS IN PATIENTS WITH SUSPECTED GIANT CELL ARTERITIS WITH NEGATIVE SCAN AT PRESENTATION
Authors: A. Verdiyeva, L. James, D. Kurzeja, J. Martinho, R. Luqmani
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Giant cell arteritis (GCA) is a medical emergency due to its risk of severe ischaemic complications such as irreversible blindness [1]. Treatment with systemic glucocorticoids (GC) should be initiated to prevent these complications promptly. However, this can compromise the confirmation of the diagnosis by decreasing the sensitivity of the temporal and axillary artery ultrasound scan (TA and AX US) recommended for GCA diagnosis [1-3]. One possible strategy for managing patients with symptoms suggestive but not typical of GCA, who have an initial negative TA and AX US on GC treatment, is weaning the GC rapidly and performing a second ultrasound off GC, within six weeks of their initial ultrasound. This practice aims to increase the diagnostic yield of the second ultrasound and safely rule out GCA without submitting the patient to unnecessary GC treatment. <h3>Objectives</h3> To assess the safety of repeating a TA and AX US after a rapid GC taper in patients with suggestive but not typical symptoms of GCA and a negative first ultrasound on a high dose GCs. <h3>Methods</h3> This is a retrospective study that included patients with suspected GCA referred to the Rheumatology department at Nuffield Orthopaedic Centre - Oxford, from Oct 2020 to June 2022. The inclusion criteria were: i) negative first TA and AX US while on treatment with GCs ≥30mg/d; ii) first ultrasound performed at least 6 months prior to the data collection; iii) second ultrasound performed within 6 weeks of the first one. The TA and AX US was considered positive when a non-compressible halo sign was present. Data regarding patient demographics, clinical manifestations, treatment, and outcomes was collected using Electronic Patient Records (EPR). The patients' records were also reviewed to check for any subsequent diagnosis of large vessel vasculitis (LVV) within 6 months of the first TA and AX US. <h3>Results</h3> Twenty-nine patients were included, 19/29 (65.5%) were females and the median age at the time of the referral was 65 (range 51-87). The most frequent clinical manifestation at presentation was temporal headache in 23/29 (79.3%) patients, followed by scalp tenderness in 18/29 (62.3%) and visual disturbance in 15/29 (51.7%). Patients were on GC treatment for a median duration of 10 days (range 3-35) with a median cumulative dose of 480mg (range 120 – 1400mg). All patients were on high doses of GCs, of whom 8/29 (27.6%) were on 60mg of prednisolone, 2/29 (6.9%) on 50mg, 17/29 (58.6%) on 40mg and 2/29 (6.9%) on 30mg. GCs were weaned over an average of 12 days (range 0-28). The second ultrasound was performed after stopping GC treatment for a median of 11 days (range 3-30) and the median interval between the two scans was 23 days (range 6-42). Regarding the second ultrasound, 28/29 (96.5%) patients had a negative and 1/29 (3.4%) had a positive TA and AX US. Moreover, 2/29 (6.9%) patients were found to have LVV on subsequent Positron Emission Tomography (PET) scans that were requested due to clinical suspicion of extra-cranial GCA. <h3>Conclusion</h3> This study shows that for patients presenting with symptoms suggestive but not typical of GCA, who were already on GC treatment, rapid taper of GCs and a negative second TA and AX US safely ruled out GCA in 26/29 (89.6%) patients. Although more studies are needed to confirm these preliminary results, this practice should maintain a good diagnostic ability but prevent unnecessary GC toxicity. <h3>References</h3> [1]Ponte C, Martins-Martinho J, Luqmani RA. Diagnosis of giant cell arteritis. Rheumatology. May 2020;59 (Supplement_3): iii5–16 [2]Dejaco C, Ramiro S, Duftner C, Besson FL, Bley TA, Blockmans D, et al. EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice. Ann Rheum Dis. May 2018;77(5):636–43 [3]Pinnell J, Mehta P, Tiivas C, Dubey S. Corticosteroids reduce vascular ultrasound sensitivity even with short duration: results from Coventry Multi-disciplinary Fast Track Pathway for management of Giant Cell Arteritis. Scand J Rheum. Apr 2022 <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.